KLF Loss-of-Field Relay
41-748P
9
Table 1
Recommended Settings for KFL Relay
Zone 1 (Alone)
Zone 2 (Alone)
Both Zone 1 and Zone 2
IMPEDANCE SETTING
See Figure 5
See Figure 6
See Figures 5 & 6
VOLTAGE SETTING
(a) Contact shorted or
(b) Set at 80% for security
80%
Zone 1 voltage contact
shorted with Zone 2 set
at 80%
TD-1
1/4 to 1 sec
(1 sec preferred)
1/4 to 1 sec
(1 sec preferred)
Zone 1 timer = 1/4 sec
Zone 2 timer = 1 sec
TD-2
Not required for
(a) above
(b) for above use 1 min.
1 min.
1 min.
ADVANTAGES
Less sensitive to stable
system swings
1) More sensitive to
LOF condition
2) Can operate on
partial LOF
3) Provide alarm
features for manual
operation
(1) Same as 1), 2) and
3) at left.
(2) Provides back-up
protection
Table 2
Special Settings for Multi Machines Bussed at Machine Terminals
Zone 1 (Alone)
Zone 2 (Alone)
Both Zone 1 and Zone 2
IMPEDANCE SETTING
See Figure 5
See Figure 6
See Figures 5 & 6
VOLTAGE SETTING
(a) Contact shorted or
(b) Set at 87% for security
87%
Zone 1 voltage contact
shorted with Zone 2 set
at 87%
TD-1
1/4 to 1 sec
(1 sec preferred)
1/4 to 1 sec
(1 sec preferred)
Zone 1 timer = 1/4 sec
Zone 2 timer = 1 sec
TD-2
Not required for
(a) above
(b) for above use 10 sec
for cond. cooled, 25 sec
for conv. cooled
10 sec for cond. cooled
25 sec for conv. cooled
10 sec for cond. cooled
25 sec for conv. cooled
